7. PROJECT SUMMARY/ABSTRACT Caregivers play a pivotal role in shaping child development, with lasting influences documented into adulthood. Responsive caregiving is a highly conserved behavior that promotes children's social and emotional development, particularly in the first few years of life. Responsive caregiving is supported by neural regions associated with reward processing. However, chronic stress and early adversity can disrupt caregiver reward processing and have negative downstream effects on responsive caregiving. Increased stress is associated with a blunted reward positivity (RP), which is an event-related potential generated after receiving feedback that indicates a reward. The RP is also elicited during in vivo observation of another receiving a reward (observational RP). Functional theories of the observational RP suggest that it represents the motivational significance and reward of another's actions. Recently, the observational RP has been used to examine caregiver neural processing of child rewards, suggesting that the caregiver observational RP may be a potential neurobiological indicator of responsive caregiving. The overall objective of this project is to use electroencephalogram (EEG) to examine caregivers' neural responses to their child's behavior as a potential indicator of caregiving reward, and to explore a possible neurobiological mechanism of the impacts of caregiver stress on responsive caregiving. Ninety caregiver?child dyads (child age 3?6 years) will be recruited to participate in the proposed study. To measure caregiver reward processing, caregiver EEG will be collected during two separate tasks, counterbalanced across participants. In the first task, caregivers will complete a guessing task in which the caregiver's neural responses to their own rewards (RP) and non-rewards (feedback negativity; FN) will be measured. In the second task, children will complete an analogous guessing task, and caregiver neural responses to observing their child's rewards (observational RP) and non-rewards (observational FN) will be measured. Dyads will complete a standardized caregiver?child interaction task that will be coded on specific features of responsive caregiving, and caregivers will report about stress and early adversity. To achieve this goal, this project will pursue the following aims: (1) examine the extent to which the caregiver observational RP predicts caregiving reward, (2) determine the degree to which caregiver stress is associated with a reduced observational RP, and (3) determine the extent to which the caregiver observational RP mediates the association between caregiver stress and responsive caregiving. Upon completion of this project, I will have developed and validated a neural indictor of caregiving reward that can be readily used to explore the impact of stress on caregiver neurobiology. I will also receive in-depth training in (a) stress and early adversity, (b) translational neuroscience, and (c) prevention science.